JP2003103216A - Forming method for multi-color pattern coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method for a mat multi-color pattern coating film with a small dispersion of painted film thickness, a uniform film thickness, an excellent decoration property, color dropping off resistance, contamination- resistance against an oily ink and weather resistance even a moving speed of an object to be coated is fast. SOLUTION: In the method for forming a mat multi-color pattern coating film having 10 or lower of 60 deg. mirror surface glossiness, a plurality of paints having different colors are spray-coated and baked on a moving bank-like object to be coated. The each paint is a shrinkable mat coating film forming paint containing (A) a hydroxyl group-containing organic resin, (B) a low nuclide methylated melamine resin, (C) a reaction mixture of 1 mol of sulfonic acid compound and 1.5 mol or higher of amine compound and (D) a coloring pigment. When a spray-coating is carried out, two or more of spray coating devices having two or more of paint delivery nozzles are employed and the paints of different colors are delivered from at least two paint delivery nozzles of the respective spray coating device to form a plurality of unit combined color spray patterns in which the paints of different colors are mixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a multi-color pattern coating film by spray coating, which can form a uniform matte multi-color pattern coating film even in high-speed coating such as coil coating.

[0002]

2. Description of the Related Art Conventionally, when spraying a moving object to be coated, since the spray gun is reciprocated largely in the width direction of the moving object to be painted. The locus becomes a large zigzag shape. Therefore, when the moving speed of the object to be coated is increased, usually 4 m / min or more, there are problems such as an unpainted portion on the object to be coated and a large variation in the coating film thickness.

When a multicolor pattern is formed on an object to be coated, it is particularly necessary to reduce the variation in the coating film thickness because the variation in the pattern due to the variation in the coating film thickness becomes remarkable. Also, it is possible to increase the reciprocating speed of the spray gun to eliminate the occurrence of unpainted parts and variations in the coating film thickness, but if the reciprocating speed is increased,
There is a problem that the straightness of the paint particles varies greatly depending on the size of the paint particles ejected from the nozzle, and the pattern pattern is disturbed.

As one means for solving the above problems, Japanese Unexamined Patent Publication No. 2000-296357 discloses that two or more spray coating devices having two or more paint discharge nozzles are used and each spray coating is performed. At least two paint discharge nozzles of the apparatus discharge different paint colors to form a plurality of unit multi-color spray patterns in which the different paint colors are mixed, and thereby, on the object to be coated, By performing spray coating so that each unit multicolor pattern pattern composed of multiple unit multicolor spray patterns partially overlaps the unit multicolor pattern pattern composed of adjacent unit multicolor spray patterns, A method for forming a uniform, multi-color pattern coating film with excellent aesthetics by spray painting in high-speed painting such as coating It has been disclosed.

Although the above problems can be solved by this method, when the multicolor pattern coating film is a low gloss matte coating film containing a large amount of extender pigment such as silica, it is formed. The multi-color pattern coating film does not have sufficient discoloration resistance, stain resistance to oil-based inks, etc., and the difference in weather resistance of each color of the multi-color pattern is large, and the appearance of the multi-color pattern coating film deteriorates over time. There is a big problem.

The object of the present invention is to provide a uniform coating film with a small variation in the coating film thickness even if the moving speed of the object to be coated is increased, and to have excellent color fading resistance, stain resistance to oil-based ink and the like, and It is intended to provide a method for forming a matte multicolor pattern coating film having excellent weather resistance by spray coating.

[0007]

Means for Solving the Problems The inventors of the present invention have now, as a paint, a reaction mixture of a sulfonic acid compound and a large excess of an amine compound in a resin system of a hydroxyl group-containing resin and a low molecular weight methylated melamine resin. A matte coating film-forming paint blended with is used, two or more spray coating devices having two or more paint discharge nozzles are used, and a part of each multicolor pattern formed by a plurality of spray patterns is By overlapping the multicolor pattern pattern formed by a plurality of spray patterns, it is possible to form a uniform multicolor pattern pattern, and it has been found that the above object can be achieved and the present invention has been completed. .

Thus, according to the present invention, a moving belt-shaped object to be coated is spray-coated with a plurality of paints having different paint colors and baked to give a 60-degree specular gloss of 10 measured according to JIS K5400 7.6 (1990). A method for forming a shrinkable matte multicolor pattern coating film, comprising: (A) a hydroxyl group-containing organic resin 60 to 95;
Parts by weight and (B) low-nuclear-body methylated melamine resin 5-4
A resin composition containing 0 parts by weight in a proportion such that the total amount of these two components is 100 parts by weight, 1 mol of the (C) sulfonic acid compound, and a boiling point in the range of 30 to 250 ° C. The resin composition 1 in which the reaction mixture with 1.5 mol or more of at least one amine compound selected from secondary amine and tertiary amine is converted into the sulfonic acid compound.
0.1 to 3 parts by weight per 00 parts by weight, and (D) a shrinkable matte coating film-forming coating material containing a color pigment, and (i) two or more coating material discharge nozzles during spray coating. Two or more spray coating devices are used, and the respective paint discharge nozzles are arranged toward the surface of the object to be coated, and (ii) paints having different paint colors from at least two paint discharge nozzles of each spray coating device. Is discharged to form a plurality of unit multi-color spray patterns in which paints of different coating colors are mixed, and (iii) thereby, on the article to be coated,
Each unit multicolor pattern pattern composed of the plurality of unit multicolor spray patterns partially overlaps the unit multicolor pattern pattern composed of the adjacent unit multicolor spray patterns to cover the entire width of the object to be coated. It is intended to provide a method for forming a shrinkable matte multicolor pattern coating film, which is characterized by forming a multiple multicolor pattern pattern.

The present invention also provides a matte multicolor pattern paint film-forming coated plate obtained by the above method for forming a multicolor pattern paint film.

The present invention will be described in more detail below.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for forming a matte multicolor pattern coating film of the present invention, a plurality of shrinkable matte coating film-forming paints having different coating colors are used. Each of the matte coating film-forming paints used is a hydroxyl group-containing resin (A), a low-nuclear-body methylated melamine resin (B), a reaction mixture (C) of a sulfonic acid compound and an amine compound, and coloring described below. It contains a pigment (D).

Hydroxyl group-containing organic resin (A) As the hydroxyl group-containing organic resin (A) which is a base resin component in the matte coating film-forming coating material, any organic resin for hydroxyl group-containing coating material can be used without particular limitation. be able to. The hydroxyl value of the hydroxyl group-containing organic resin is generally 5 to 110 mgKOH / g, from the viewpoint of solvent resistance, processability and the like.
It is particularly preferable that the amount is in the range of 10 to 80 mgKOH / g, and examples of the resin type include polyester resin, acrylic resin, fluororesin and the like. Among them, a hydroxyl group-containing polyester resin can be preferably used.

Examples of the hydroxyl group-containing polyester resin include oil-modified polyester resin, oil-free polyester resin, acryl-modified polyester resin, and silicon-modified polyester resin, which are generally used as polyester resins for paints. The polyester resin preferably has a number average molecular weight in the range of generally 600 to 30,000, particularly 1,000 to 25,000. These polyester resins can be used alone or in combination of two or more kinds.

[0014] Teikakutai methylated melamine resin (B) low-nuclear methylated melamine resin, which is a crosslinking agent component in matted coating film-forming coating material (B) is a low nucleus melamine resin having a methoxy group by methylation And has substantially no NH group, an average degree of condensation (average number of triazine nuclei) of 2.5 or less, and an average of 4 or more alkoxy groups per triazine nucleus, particularly 4 It is a melamine resin containing 5 to 6 and of which 2.5 or more, especially 4 to 6 methoxy groups, and particularly preferably a melamine resin containing 40 wt% or more of a hexamethoxymethylmelamine mononuclear body. Examples of the alkoxy group which can coexist with the methoxy group include C _{2 to} C ₆ such as ethoxy group, n-propoxy, isopropoxy, n-butoxy group and isobutoxy group.
An alkoxy group is mentioned.

The low-nuclear-body methylated melamine resin (B) is known, and for example, Cymel 300, Cymel 303, Cymel 370, Cymel 232, Cymel 235, Cymel 238, Cymel 272, [all of which are manufactured by Mitsui Cytec Co., Ltd. , Trade name], Nikarac MW30, Nikarac MW22A [all above, product name by Sanwa Chemical Co., Ltd.], Sumimar M100 [product name by Sumitomo Chemical Co., Ltd.], Regimin 747, Regimin 745, Regimin 75
It is possible to use commercially available products such as 5 [all above, manufactured by Monsanto Co., Ltd., trade names].

These low-nuclear methylated melamine resins (B) undergo a sufficient curing reaction with the hydroxyl group-containing organic resin (A) by baking for a short time in the presence of a strong acid catalyst.
In the absence of a strong acid catalyst, generally, short-time baking does not cause a sufficient curing reaction with the hydroxyl group-containing organic resin (A). The above low-nucleus methylated melamine resins can be used alone or in combination of two or more.

The mixing ratio of the hydroxyl group-containing organic resin (A) and the low-nucleus methylated melamine resin (B) is from the viewpoints of curability, solvent resistance of the resulting coating film, corrosion resistance and processability. Based on a total of 100 parts by weight of the resin solids of both, the component (A) is 60 to 95 parts by weight, preferably 70 to 92 parts by weight, and the component (B) is 5 to 5 as the resin solids. It is suitable to be in the range of 40 parts by weight, preferably 8 to 30 parts by weight.

Reaction of Sulfonic Acid Compound with Amine Compound
Mixture (C) The matte coating film-forming coating material used in the present invention has a sulfonic acid compound as a curing catalyst, a large excess equivalent boiling point of 30 to 250 ° C., a secondary amine and a tertiary amine. It contains a reaction mixture (C) with at least one amine compound selected from primary amines.

The reaction mixture (C) can be easily obtained by mixing the sulfonic acid compound and the amine, for example, at room temperature. The component (C) may be added as a reaction mixture obtained by previously mixing and reacting a sulfonic acid compound and an amine compound at a predetermined ratio when producing a matte coating film-forming coating material. The compound and the amine compound may be separately blended into the coating material, or the reaction product of the sulfonic acid compound and a part of the amine compound and the remaining amine compound may be separately blended into the coating material.

The sulfonic acid compound is a secondary amine or a tertiary amine.
Although the catalytic action is temporarily suppressed by the formation of an amine salt with a primary amine, the sulfonic acid compound is originally a curing compound between the hydroxyl group-containing organic resin (A) and the low-nuclear methylated melamine resin (B). It is a catalyst that accelerates the reaction, and acts as a curing catalyst in the surface layer of the coating film by volatilizing the amine compound from the surface of the coating film during baking of the coating film, but inside the coating film, the volatilization of the amine compound is slow, Since a large amount of the amine compound remains in the initial stage of baking, its action as a curing catalyst can be suppressed. Therefore, it is considered that a large time difference occurs between the surface curing and the internal curing of the coating film, and a matte coating film due to a shrinkage pattern is formed on the coating film surface.

Examples of the sulfonic acid compound include:
Alkylaryl sulfonic acids such as dodecylbenzene sulfonic acid, dinonyl naphthalene disulfonic acid, dinonyl naphthalene sulfonic acid, paratoluene sulfonic acid; alkyl sulfonic acids such as methane sulfonic acid, etc., which may be used alone or in combination of two or more. Can be used.

The secondary or tertiary amine compound used to form the salt with the sulfonic acid compound is 30
To 250 ° C., preferably having a boiling point in the range of 50 to 230 ° C., and specifically, for example, diethylamine, diisopropylamine, di-n-propylamine,
Diallylamine, diamylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine,
N-ethyl 1,2-dimethylpropylamine, N-methylhexylamine, di-n-octylamine, piperidine, 2-pipecoline, 3-pipecoline, 4-pipecoline, 2,4-, 2,5-or 3, 5-lupetidine,
Secondary amines such as dimethyloxazolidine and 3-piperidinemethanol; triethylamine, N-methylmorpholine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N, N ', N'-
Tetramethyl-1,2-diaminoethane, N, N,
N ', N'-tetramethyl-1,3-diaminopropane,
Examples thereof include tertiary amines such as N-methylpiperidine and pyridine. Of these, dimethyloxazolidine and dialkylamines, particularly diisopropylamine, di-n-propylamine, di-n-butylamine, diisobutylamine and the like, are preferred because they have a low odor and form a beautiful tinge.

The mixing ratio of the sulfonic acid compound and the amine compound in the component (C) is 1.5 or more in terms of amine compound / sulfonic acid compound molar ratio from the viewpoint of the matte coating film forming property due to the wrinkle pattern. Suitably, it is preferably in the range of 4 to 30, more preferably 6 to 20 mol.

The amount of the reaction mixture of the sulfonic acid compound and the amine compound, which is the component (C), to be added to the coating composition is the same as the amount of the component (A) (from the viewpoint of curability, water resistance and moisture resistance of the coating film). The total amount of 100 parts by weight with the component B) is 0.1 to 3 parts by weight, preferably 0.2 to 2 parts by weight, calculated as the amount of the sulfonic acid compound. In the present specification, the “amount converted into the amount of sulfonic acid compound” means the amount of sulfonic acid compound that constitutes the reaction mixture.

Coloring Pigment (D) As the coloring pigment (D) to be blended in the matte film-forming coating material, a coloring pigment known per se used in conventional coating materials can be used.

Specific examples of the color pigment (D) include carmine FB, dinitroaniline orange, pyrazolone orange, pyrazolone red, perinone orange,
Permanent Red 2B, Rake Red R, Bon Maroon Light, Bordeaux 10B, Bon Maroon Medium,
Thio Indigo Bordeaux, Bon Maroon L, Perylene Vermillion, Perylene Scarlet, Perylene Maroon,
Red pigments such as benzimidazolone orange, chrome vermillion molybdenum red, red iron oxide, toluidine red, γ-quinacridone red; cyanine blue pigment blue 15, same 15: 1, same 15: 2, same 15: 3, same 15: 4 , Blue pigments such as metal-free cyanine blue, indanthrene blue, navy blue, ultramarine blue, cobalt blue; monoazo yellow pigment, disazo yellow pigment, condensed azo yellow pigment, isoindolinone yellow pigment, slene-based yellow pigment, metal complex yellow pigment, Quinophthalone yellow, isoindoline yellow, yellow lead, yellow iron oxide,
Yellow pigments such as titanium yellow; black pigments such as carbon black, pine smoke, graphite, iron black; white pigments such as titanium white and zinc white; cobalt green, cyanine green, brominated green, titanium / nickel / cobalt / zinc type Green pigments such as green; purple pigments such as cobalt violet, manganese violet, dioxazine violet, β-quinacridone violet; mica-like iron oxide powder, pearl-like mica powder, aluminum powder, bronze powder, copper powder,
Examples thereof include bright pigments such as stainless steel powder and nickel powder. These color pigments may be used alone or in combination of two or more.

The blending amount of the color pigment is not particularly limited and can be appropriately changed depending on the type of the color pigment and the desired coating color, but usually, the (A) component and the (B) component are used. The total amount is preferably 5 to 120 parts by weight, and particularly preferably 8 to 100 parts by weight per 100 parts by weight.

Each matte coating film-forming coating material used in the method of the present invention contains the above-mentioned components (A), (B), (C) and (D) as essential components, and is usually an organic material. Contains a solvent, and if necessary, fine silica powder, aggregate;
An extender pigment such as talc, clay, mica, alumina, silica-alumina ceramic powder; a rust preventive pigment such as strontium chromate and zinc chromate; and other additives for paints may be contained.

The fine silica powder generally has an average particle size of 1
A fine silica powder having a particle size of 0 μm or less, preferably 0.5 to 8 μm is preferable, and by incorporating this, the corrosion resistance of the Chijimi coating film, particularly the corrosion resistance of the recessed portion and the cut portion can be improved. The particle diameter in the present specification is a particle diameter in a state of being dispersed in a paint, and is a so-called secondary particle diameter. The fine silica powder may be produced by any of a wet method and a dry method, or may be one whose surface is treated by coating or the like. The fine silica powder is usually added in an amount of 15 parts by weight or less, preferably 1 to 10 parts by weight, per 100 parts by weight of the total of the components (A) and (B), the corrosion resistance and weather resistance of the coating film. It is suitable from the standpoint of properties and color fastness.

Typical examples of silica fine powders are, for example, trade names of Aerosil 200, 300, 380 and T.
T600 [above, manufactured by Nippon Aerosil Co., Ltd.], Syloid 74, 83, 161, 162, 244, 3
08, 378 [Fuji Silysia Chemical Ltd.],
Mizukacil P-526, P-527, P-801,
Same NP-8 [above, Mizusawa Chemical Co., Ltd.], Nipseal E200A, same E220 [above, Nippon Silica Industry Co., Ltd.], Fineseal E-50, same E-70, same T-32, same. X-37 [above, manufactured by Tokuyama Soda Co., Ltd.], Carplex # 67, and # 80 [above, manufactured by Shionogi Pharmaceutical Co., Ltd.] and the like.

The above aggregates, which can be optionally incorporated in each matte coating film-forming coating material, improve the pattern stability of the formed wrinkle pattern coating film and further improve the designability. (A) Average particle size 2 to 70 μm
m, preferably 5 to 30 μm organic resin particles, (b) diameter 2 to 50 μm and length 30 μm to 5 mm, preferably diameter 3 to 30 μm and length 50 μm to 3 mm and length / diameter ratio 2 /. 1-100 / 1 organic resin fiber,
(C) Average particle size 2 to 70 μm, preferably 5 to 30 μm
Glass particles of (d) and a diameter of 2 to 50 μm and a length of 10
μm to 5 mm, preferably 3 to 30 μm in diameter and 30 in length
μm to 3 mm and a length / diameter ratio of 2/1 to 10
It may be one or a combination of two or more such as 0/1 inorganic fibers.

It is necessary that the above-mentioned aggregate is not dissolved in the solvent in the coating material and is not completely melted at the coating film forming temperature (that is, the coating film curing condition in the practical coating line). The phrase "not completely melted" includes not only a completely unmelted state but also a partially melted state in which the peripheral surface of each particle or fiber is covered with the melt.

Examples of the organic resin particles in the component (a) include polyolefins such as polyethylene and polypropylene; acrylic resins such as polyacrylonitrile and polymethylmethacrylate; fluorine-containing resins such as polytetrafluoroethylene and polyvinylidene fluoride; nylon. Examples thereof include polyamide resins such as 11 and nylon 12; amino resins such as benzoguanamine resin and melamine resin; resin particles such as silicone resin, urethane resin, polyester resin, polystyrene, phenol resin, epoxy resin and cellulose. Examples of the organic resin fiber (b) include fibers such as polyester resin, acrylic resin, polyamide resin, and cellulose.

Examples of the glass particles (c) include silicate glass, which may be hollow. Examples of the inorganic fiber (d) include fibers such as glass, potassium titanate, carbon, and basic magnesium sulfate. Among the aggregates of (a), (b), (c), and (d) above, it is preferable to use the aggregates of (a) and / or (b) from the viewpoint that a soft feeling is obtained. preferable.

Pattern stability of the coating film formed by blending the above-mentioned aggregate in the paint (uniform expression of the pattern)
Can be improved, and the design can be further improved by giving a change to the pattern. As the aggregate, particles having a particle size of 5 μm or more and fibers having a diameter of 5 μm or more,
It is more preferable because the pattern can be easily changed. The aggregate is generally 30 parts by weight or less, preferably 5 parts by weight per 100 parts by weight of the total of the components (A) and (B), from the viewpoints of weather resistance, discoloration resistance, processability, etc. of the coating film.
It is preferable to blend within the range of 15 to 15 parts by weight. In the method of the present invention, the matte coating film-forming coating composition is spray-coated on a belt-shaped article which moves at a speed of 10 m / min or more, preferably 10 to 150 m / min, more preferably 20 to 80 m / min, By baking and curing, JI
A shrinkable matte multicolor pattern coating film having a 60 degree specular gloss of 10 or less as measured by SK5400 7.6 (1990) is formed.

According to the present invention, the spray coating includes (i)
Two spray coating devices with two or more paint discharge nozzles
Using at least two bases, arranging the respective paint discharge nozzles toward the surface of the object to be coated, and (ii) discharging paints of different coating colors from at least two paint discharge nozzles of each spray coating device, A plurality of unit multicolor spray patterns in which paints of different coating colors are mixed are formed, and (iii) thereby, each unit multicolor pattern pattern composed of the plurality of unit multicolor spray patterns is formed on the article. This can be performed by forming a multi-color multi-color pattern that partially overlaps the multi-color pattern pattern of the unit composed of adjacent multi-color spray patterns and covers the entire width of the object to be coated.

As a spray coating apparatus having two or more paint discharge nozzles used in the method of the present invention,
For example, a multi-nozzle spray gun, a multi-head spray gun, etc. can be mentioned.

The multi-nozzle spray gun is a coating machine having one coating gun head in the coating machine and two or more coating discharge nozzles adjacent to the coating gun head. It is possible to discharge the paints of different paint colors from the paint discharge nozzles of the multi-nozzle spray gun to form a multi-color spray pattern in which the paints of different paint colors are mixed.

As the multi-nozzle spray gun, for example,
The spray gun described in JP-A-9-299833 can be mentioned. The position of the nozzle of the multi-nozzle spray gun may be a position where the paints of different colors ejected from the respective nozzles can be mixed and a uniform pattern paint layer can be formed on the object to be coated. One or more nozzles may be independently arranged, or each nozzle may be integrally concentrically arranged to form an inner nozzle and an outer donut-shaped nozzle.

An example of a spray coating apparatus in which two or more nozzles are independently arranged will be described with reference to FIGS. 1 and 2 below.

FIG. 1 is a front sectional view of the spray coating apparatus, and FIG. 2 is a left side view of the spray coating apparatus. 1 is a cross-sectional view taken along the line AA in FIG. 2 which is a left side view.

In FIG. 1, the spray coating apparatus comprises a gun body 1, a paint discharge nozzle base 5, an air cap 15, and a retaining nut 14 for fixing these by coupling them.

The gun body 1 has a paint supply port 2 (a, b,
c, d; however, c and d are not shown), atomizing air supply port 3
(A, b; b is not shown), a pattern air supply port 4 (a, b; b is not shown) and a pilot air supply port 19 are formed. Further, from the paint supply port 2 to the left in FIG. 1, paint paths 6 (a, b, c, d;
However, c and d are not shown), the atomizing air path 9 (a, b; however, b is not shown) from the atomizing air supply port 3 to the left,
Pattern air path 1 from the pattern air supply port 4 to the left
0 (a, b; b is not shown) and a pilot air passage 20 is formed in the upper right portion from the pilot air supply port 19.

The paint discharge nozzle base 5 has a paint path 7
(A, b, c, d; however, c and d are not shown), atomizing air path 11 (a, b, c, d; but c and d are not shown), and paint discharge nozzle 8 ( a, b, c, d; provided that
c and d are not shown). Air cap 15
Atomized air ejection port 16 is formed in the central portion of the and the pattern air ejection port 17 (a, b) is formed in the horn portion. By fixing the paint discharge nozzle base 5, the air cap 15, and the paint discharge nozzle position adjusting washer 18 with the retaining nut 14, the atomizing air supply chamber 12 and the pattern air supply chamber 13 are formed.

At the time of painting, the paint path 6 of the gun body 1
Communicates with the paint passage 7 of the paint discharge nozzle base, and the paint is supplied to the paint passage 7 of the paint discharge nozzle base from the left end of the paint passage 6 of the gun body 1 and can be further discharged from the paint discharge nozzle 8. ing. The atomizing air is supplied from the atomizing air path 9 of the gun body 1 to a chamber communicating with the atomizing air path 11 of the paint discharge nozzle base, and enters the atomizing air supply chamber 12 from this chamber via the atomizing air path 11. It is ejected from the atomizing air ejection port 16. The spray of the atomized air atomizes the paint discharged from the paint discharge nozzle 8. The pattern air is the pattern air path 1 of the gun body 1.
It is supplied to the pattern air supply chamber 13 from 0 and is ejected from the pattern air ejection port 17. By spraying the pattern air, it is possible to accelerate the atomization of the paint particles and increase the spray pattern width of the paint.

The pilot air supplied from the pilot air supply port 19 of the gun body 1 is supplied to the pilot air passage 2
It is supplied to the closed pilot air supply chamber 21 formed by the inner wall of the gun body 1 and the piston 24 via 0. By supplying the pilot air to the pilot air supply chamber 21, the piston 24 is pushed to the right and moved to expand the pilot air supply chamber 21. As a result, the needle connecting member 22 connected to the piston 24 and the needle 23 (a, b,
c, d; provided that c and d are not shown) move to the right. By moving the needle 23 to the right, the paint passage 6 of the gun body 1 and the paint passage 7 of the paint discharge nozzle base communicate with each other, and the paint can be discharged.

When the pilot air is not supplied, the spring 25 pushes the piston 24 and the members interlocking with the piston 24 toward the left end, so that the left end of the needle 23 opens the right end of the paint passage 7 of the paint discharge nozzle base 5. The paint passage 6 of the gun body 1 and the paint passage 7 of the paint discharge nozzle base do not communicate with each other and the paint is not discharged. It is also possible to adjust the amount of paint to be discharged by adjusting the position of the needle drawing allowance positioning member 27 with the needle drawing allowance adjusting screw 26.

Next, in FIG. 2, four paint discharge nozzles 8 (a, b, c, d) are arranged in the central portion, and atomized air is ejected from the atomized air ejection port 16 in the vicinity thereof. Is
Further, pattern air is ejected from the pattern air ejection port 17 (a, b). It is possible to form a multicolor pattern by using two or more of the four paint discharge nozzles, discharging paints of different coating colors from each nozzle, and ejecting atomized air and pattern air.

The degree of mixing of the paint particles can be adjusted by changing the arrangement of the paint discharge nozzles 8 (a, b, c, d). That is, as shown in FIG. 2, it is possible to increase the mixing degree of the paint particles discharged from each paint discharge nozzle by bringing the paint discharge nozzle members close to each other so that they can contact each other. When the paint discharge nozzle members are separated from each other, the mixing degree of the paint particles becomes small. The distance between the paint discharge nozzles is not particularly limited, but it is usually preferable that the paint discharge nozzles be as close as possible, and the distance between the centers of the paint discharge nozzles is 15 mm or less, preferably 10 mm or less. , And more preferably, it is within the range of 5 mm or less.

When the multi-nozzle spray gun has three or more paint discharge nozzles (four in FIG. 2), different paint colors may be discharged from the respective paint discharge nozzles, or a required number of paints may be discharged. The paints of different coating colors may be sprayed using only the nozzles (for example, two nozzles out of four nozzles).

In the multi-head spray gun, the coating machine has two or more coating gun heads, each coating gun head has one paint discharge nozzle, and the paint discharge nozzles are not close to each other. The paint discharge nozzles (two or more in total) of each paint head of the multi-head spray gun are made to face toward the object to be coated, and spray patterns of paint particles of different paint colors discharged from two or more paint discharge nozzles are formed. It is possible to form a multicolor pattern coating film by forming a multicolor spray pattern in which paints of two or more different coating colors are mixed with each other to cross each other before hitting the surface to be coated. In addition, the directions of the nozzles of the two air spray guns intersect each other before the spray patterns hit the surface to be coated to form a multicolor spray pattern, so that a multicolor pattern coating film can be formed on the object. When positioned and fixed, it can function like a multi-head spray gun.

At least two spray guns having two or more paint discharge nozzles using the above spray coating apparatus.
At least two different paint colors are discharged from each paint discharge nozzle. As a result, a multi-color spray pattern in which the paint discharged from each nozzle is mixed is formed. The mixing degree of the paint in the spray pattern may be determined according to the target pattern within the range where a multicolor pattern coating film can be formed. Appropriately adjust the coating conditions such as paint viscosity and paint discharge amount. Can be adjusted by. When painting, the viscosity of the paint is usually a Ford Cup #
It is suitable that the measurement at 4 (20 ° C.) is usually within the range of 10 to 40 seconds. The atomizing air pressure of the paint is usually
It is suitable that the pressure is in the range of 0.5 to 10 kgf / cm ² , and the pattern air pressure is usually in the range of 0.1 to 4 kgf / cm ² .

The shape of the unit multicolor spray pattern from each coating device formed as described above may be a perfect circle or an ellipse, and is not particularly limited.

In the present invention, a plurality of unit multicolor spray patterns formed by a plurality of spray coating devices are combined to form a multiple multicolor pattern pattern in which adjacent unit multicolor pattern patterns are partially overlapped. The degree of overlap between adjacent unit multicolor pattern patterns is generally such that, on a line connecting the centers of the unit multicolor pattern patterns, the width of the overlap is 1/6 to 1/2, preferably 1 of the length of the line. /
Within the range of 3 to 1/2 (when each unit multicolor pattern is a circle, 1/6 to 1/2 of its diameter, preferably 1)
It is preferably within the range of / 3 to 1/2). In the present invention, the size of the unit multicolor pattern pattern or the multicolor pattern pattern means the size of the effective spray pattern.

When forming a multicolor pattern on an object to be coated, the coating machine is subjected to short reciprocation (short-distance reciprocating motion) in the width direction of the belt-shaped object to be coated to form a multicolor pattern. You may reciprocate in the width direction. It is possible to improve the uniformity of the pattern by performing short reciprocation.

In the present invention, when forming a multicolor pattern by spray coating, the multicolor pattern pattern is continuously coated so as to cover the entire width of the object. When performing a short reciprocating coating machine, the short reciprocating is performed so that the multi-color pattern pattern continuously covers the entire width of the object to be coated.

The coating amount of the multicolor pattern layer formed on the article to be coated is not particularly limited, but the coating amount is usually 0.5 to 120 g / m ² in terms of coating solid content. It is preferably in the range of 1 to 80 g / m ^{2 from} the viewpoints of the appearance of the obtained patterned coating film and prevention of bubbling (foaming) of the coating film during baking.

In the method of the present invention, the strip-shaped article to be coated is, for example, a metal plate, a primer coating film on the metal plate, and if necessary, a coated metal plate having a colored protective coating film formed on the primer coating film. , A plastic sheet, etc., among which a metal plate or a coated metal plate can be preferably used.

Examples of the metal plate include a cold rolled steel plate, a zinc-based plated steel plate, an aluminum-plated steel plate, an aluminum plate and the like. Among them, a zinc-based plated steel plate can be preferably used. Examples of the zinc-based plated steel sheet include hot-dip galvanized steel sheet, electrogalvanized steel sheet, iron-zinc alloy-plated steel sheet, nickel-zinc alloy-plated steel sheet, aluminum-zinc alloy-plated steel sheet (for example, "Galvalium", "Galfan (Galfan)).
An) ”is a plated steel plate) and the like. Further, the surface of the metal plate may be subjected to chemical conversion treatment such as zinc phosphate treatment or chromate treatment in order to improve adhesion and corrosion resistance.

When the article to be coated is a coated metal plate, the primer coating which may be formed on the metal plate is
A coating film obtained from a polyester-based primer or an epoxy resin-based primer is suitable, and the film thickness thereof is not particularly limited, but as a cured (dry) coating film, it is usually preferably about 2 to 10 μm. . The intermediate coating film and the top coating base coating film may be a coating film formed from a conventional intermediate coating composition and top coating base coating composition in the field of coating materials. Examples of the intermediate coating material and the top coating base coating material include polyester resin-based coatings, alkyd resin-based coatings, acrylic resin-based coatings, and silicone polyester resin-based coatings.

The moving speed of the strip-shaped article to be coated is
Although not particularly limited, it is usually 10 m / min or more, preferably 10 m / min or more, from the viewpoint of productivity, coating state, and the like.
It is suitable to be in the range of 150 m / min, more preferably 20 to 80 m / min.

An example of the method of the present invention will be described with reference to FIG.

In FIG. 3, using three multi-nozzle guns 28 mounted on a coating gun fixed mount 29, three multi-nozzle guns 28 are mounted on a primer-coated steel plate 30 on which a primer coating film to be coated is formed. A multi-color multi-color pattern is formed by superimposing three unit multi-color spray patterns formed by the nozzle gun. If necessary, the three multi-nozzle guns 28 can simultaneously perform short reciprocation (short-distance reciprocating motion) in the width direction of the object to be coated. The primer-coated steel sheet on which the multicolor pattern coating film has been formed is then baked to cure the multicolor pattern coating film.

The baking conditions for the multicolor pattern coating film are not particularly limited, but in the case of continuous coating, the maximum temperature to be coated is usually 160 to 250 ° C.
About 30 seconds to 2 minutes is suitable.

[0065]

EXAMPLES The present invention will be described in more detail with reference to production examples and examples. Hereinafter, "parts" and "%" are based on weight.

Production Example 1 Weight average molecular weight 20,000 and hydroxyl value 15 mg KO
Solid content of H / g oil-free polyester resin 60%
133 parts of resin solution, 20 parts of Cymel 303 (manufactured by Mitsui Cytec Co., Ltd., a low-nuclear methylated melamine resin), 90 parts of titanium white pigment, and silica fine powder 3 having an average particle diameter of about 2 μm.
Parts and 54 parts of mixed solvent A (Note 1) are mixed and dispersed in 300 parts of a white paint base obtained by mixing 1.0 part of dodecylbenzenesulfonic acid and 2.2 parts of n-dibutylamine 3.2. The parts were mixed, and the mixed solvent A was further added and stirred uniformly to obtain a white paint-1 having a Ford cup # 4 viscosity of 20 seconds at 25 ° C.

(Note 1) Mixed solvent A: Swazol 1000
(Cosmo Oil Co., Ltd., high boiling aromatic hydrocarbon solvent) / xylene / cyclohexanone = 50/30/20 (weight ratio) mixed solvent.

Production Examples 2 to 11 The same oil-free polyester resin solution as that used in Production Example 1 was used, and the compounding composition in Production Example 1 is shown in Table 1 below.
25 ° C. by Ford cup # 4 in the same manner as in Production Example 1 except that the mixing method of the sulfonic acid compound and the amine compound was changed as shown in Table 1 below.
Each paint having a viscosity of 20 seconds was obtained. The paints obtained in Production Examples 9 to 11 are for comparison.

[0069]

[Table 1]

Example 1 As the paint, the white paint-1 obtained in Production Example 1 and the black paint-2 obtained in Production Example 2 were used.

The coating method is as shown in FIG.
This was done using four multi-nozzle guns. As an article to be coated,
KP Color 8451 Primer (Kansai Paint Co., Ltd.)
Made of epoxy resin type primer) with a dry film thickness of about 5 μm
Using a primer-coated galvanized steel sheet having a width of 80 cm after coating and baking (indicated as "coated object A" in Table 2 below), the moving speed (line speed) of the coated object was 40 m / min. .

Each multi-nozzle gun has four nozzles and the members of the nozzles are in contact with each other (distance between nozzles: 4 m
m), two of the four nozzles are used, and when two kinds of paints, the white paint-1 and the black paint-2, are respectively discharged from two nozzles and coated, the nozzle tip The distance from the surface of the object to be coated is 40 cm, the effective pattern width is 40 cm, and each unit multi-colored pattern is formed. Adjacent spray patterns are multi-colored so that 1/3 of the spray pattern diameters overlap. A pattern was formed and painted.

In each multi-nozzle gun, the atomization air pressure of the paint is 1.5 kgf / cm ² and the pattern air pressure is 1.5 k.
gf / cm ^2, and the discharge amount of the paint from each multi-nozzle gun was 250 cc / min for both the white paint and the black paint. Coating as above, baking for 45 seconds under the condition that the maximum temperature reached to the material is 220 ° C, and the amount of dry coating applied on the surface of the galvanized steel sheet coated with primer is about 40 g / m 2.
² (dry film thickness: about 10 μm), a uniform, fine, shrinking, matte, multicolor pattern coating film was formed.

Example 2 As the paint, the white paint-4 obtained in Production Example 4 and the black paint-5 obtained in Production Example 5 were used.

As an object to be coated, a KP color 8451 primer was applied to a dry film thickness of about 5 μm and baked, and then a KP color 15
A coated steel sheet obtained by coating and baking about 73 μm of white 73 enamel (Kansai Paint Co., Ltd., white polyester / melamine resin paint) (indicated as “coated object B” in Table 2 below) was used.

Moving speed (line speed) of the object to be coated 40
m / min. Pattern coating is performed in the same manner as in Example 1 except that the coating material B is used as the coating material, the plate width is 60 cm, and four double-headed guns are used instead of four multi-nozzle guns. It was

In each two-headed gun, a white spray pattern and a black spray pattern intersect so that a patterned coating film can be formed on the roll surface. When the above-mentioned two types of white and black paints are discharged from each two-headed gun, the distance from the nozzle tip to the roll surface is 70 cm, and each unit multicolor pattern with an effective pattern width of 40 cm is formed. Matching units Multicolor pattern Patterns were painted so that 1/2 of the diameter of the spray pattern overlapped. Further, during coating, four two-headed guns were simultaneously subjected to a short reciprocating distance of 15 cm in the width direction of the coating roll.

In each two-head gun, the atomizing air pressure of the paint is 2.5 kgf / cm ² , and the pattern air pressure is 1.5 kgf.
/ Cm ^2, and the discharge amount of the coating material from each nozzle was 250 cc / min for both the white coating material and the black coating material. By coating as described above and baking for 45 seconds under the condition that the maximum temperature reached by the material is 220 ° C, the surface of the coated galvanized steel sheet coated with white enamel on the primer,
Approximately 40g / m ^{2 of} dry coating film (dry film thickness of about 10μ
A uniform, fine, shrinking, matte, multicolor pattern coating film of m) was formed.

Examples 3 and 4 In Example 1, the type of article to be coated, the plate width, the type of paint used,
The same operation as in Example 1 was carried out except that the number of gun nozzles used was as shown in Table 2 below, and a dry coating amount of about 40 g / m ² (dry film thickness of about 10 μm) was applied onto the object to be coated. A uniform, fine, shrinking, matte, multicolor pattern coating was formed.

Comparative Examples 1 and 2 In Example 1, the type of article to be coated, the plate width, the type of paint used,
The same operation as in Example 1 was carried out except that the number of gun nozzles used was as shown in Table 2 below, and a dry coating amount of about 40 g / m ² (dry film thickness of about 10 μm) was applied onto the object to be coated. A matte multicolor pattern coating was formed.

The coated steel sheets having the matte multicolor pattern coating films obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated according to the following test methods.

Test method Appearance of coating film: When there is no abnormality on the coated surface and the appearance is good and matte, it is indicated as good (◯).

60 degree specular gloss: JIS K5400
The specular glossiness (60 degrees) was measured according to 7.6 (1990).

Color fading resistance: Four sheets of gauze were stacked and wound on a finger, and the surface of the coated plate was rubbed and the degree of coloring on the gauze was visually evaluated.

[0085] ◯: Gauze is not colored, △: Gauze is slightly colored, X: Gauze is considerably or markedly colored.

Oil-resistant ink stain resistance: A line was drawn on the coated surface with red oil-based ink in a room at 20 ° C., and after leaving for 1 hour,
It was wiped off with a gauze soaked with n-butanol.
The appearance of traces of red ink after wiping off was visually evaluated.
The appearance was visually evaluated according to the following criteria.

[0087]         ◎: No trace is observed, ◯: A trace is slightly observed,         Δ: Quite a trace remains, X: A trace remains thick.

Accelerated weathering resistance: A 1,000-hour test was conducted using a sunshine weatherometer. The coating film appearance of the coated plate after the test was visually compared with the coating film appearance of the untested coated plate, and judged according to the following criteria.

[0089] Good: The difference between the coated plates is small and good, △: There is a considerable difference between the two coated plates, which is slightly defective, X: There is a large difference between the two coated plates, which is defective.

[0090]

[Table 2]

[0091]

As described above, according to the method of the present invention, even if the moving speed of the object to be coated is increased, an unpainted portion does not occur on the object to be coated, and moreover, there is variation in the coating film thickness. It is possible to form a matte multicolor pattern coating film which is small and uniform, has excellent cosmetic properties, and has excellent colorfastness, stain resistance to oil-based inks, and weather resistance.

[Brief description of drawings]

FIG. 1 is a front sectional view of an example of a multi-nozzle spray gun used in the present invention.

FIG. 2 is a left side view of an example of a multi-nozzle spray gun used in the present invention.

FIG. 3 is a schematic view showing an example of a multicolor pattern forming method of the present invention.

[Explanation of symbols]

1 gun body 2 (a, b, c, d) paint supply port 3 (a, b) atomization air supply port 4 (a, b) pattern air supply port 5 paint discharge nozzle base 6 (a, b, c, d) Paint path 7 (a, b, c, d) of gun body Paint path 8 (a, b, c, d) of paint discharge nozzle base Paint discharge nozzle 9 (a, b) Atomizing air path of gun body 10 (a, b) Pattern air path 11 (a, b, c, d) of gun body Atomizing air path 12 of paint discharge nozzle base Atomizing air supply chamber 13 Pattern air supply chamber 14 Retaining nut 15 Air cap 16 Atomizing air jet 17 (a, b) Pattern air jet 18 Paint discharge nozzle position adjustment washer 19 Pilot air supply port 20 Pilot air path 21 Pilot air supply chamber 22 Needle connecting member 23 (a, b, c, d) Needle 2 The piston 25 spring 26 needle pulling white adjustment screw 27 needle pulling white positioning member 28 multi nozzle spray gun 29 coating gun fixed frame (short reciprocating device) 30 primer coated steel

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 5/28 C09D 5/28 161/28 161/28 167/00 167/00 201/06 201/06 F Term (reference) 4D075 AA01 AA39 AA52 AA58 AA65 AA85 AE04 AE07 CB02 CB21 CB32 DA03 DB02 DB05 DB07 DC10 EA07 EA41 EB22 EB32 EB33 EB35 EB36 EB42 EB55 EC03 EC07 EC11 EC13 EC37 4J038 PA06 B02 GA01 DD02001

Claims (19)

[Claims] 1. JIS K540, wherein a plurality of paints having different paint colors are spray-coated and baked on a moving strip-shaped object to be coated, according to JIS K540.
0 7.6 (1990), a method of forming a shrinking matte multicolor pattern coating film having a 60-degree specular gloss of 10 or less, wherein each of the plurality of paints comprises (A)
A resin composition containing 60 to 95 parts by weight of a hydroxyl group-containing organic resin and 5 to 40 parts by weight of (B) a low-nucleus methylated melamine resin in a proportion such that the total amount of these two components is 100 parts by weight; C) a reaction mixture of 1 mol of a sulfonic acid compound and 1.5 mol or more of at least one amine compound having a boiling point in the range of 30 to 250 ° C. and selected from a secondary amine and a tertiary amine, The amount converted to the sulfonic acid compound was 0.1 per 100 parts by weight of the resin composition.
1 to 3 parts by weight and (D) a shrinkable matte coating film-forming paint containing a color pigment, and (i) a spray coating device having two or more paint discharge nozzles for spray coating. Using at least two bases, arranging the respective paint discharge nozzles toward the surface of the object to be coated, and (ii) discharging paints of different coating colors from at least two paint discharge nozzles of each spray coating device, A plurality of unit multicolor spray patterns in which paints of different coating colors are mixed are formed, and (iii) thereby, each unit multicolor pattern pattern composed of the plurality of unit multicolor spray patterns is formed on the article. , A multi-color pattern pattern that partially overlaps a unit multi-color pattern pattern formed by adjacent unit multi-color spray patterns and covers the entire width of the object to be coated. Method of forming Jotsuya off multicolored decorative paint film. 2. The hydroxyl group-containing organic resin (A) has a hydroxyl value of 5
The method according to claim 1, wherein the polyester resin is ˜110 mgKOH / g. 3. The low-nucleus methylated melamine resin (B) comprises
Melamine resin having substantially no NH groups, an average degree of condensation of 2.5 or less, and an average of four or more alkoxy groups and one or more methoxy groups of 2.5 or more per triazine nucleus. The method according to claim 1 or 2, wherein 4. The resin composition comprises 70 to 92 parts by weight of a hydroxyl group-containing organic resin (A) and (B) a low-nucleus body, based on 100 parts by weight of the total amount of the components (A) and (B). A methylated melamine resin containing 8 to 30 parts by weight.
The method according to any one of 3 above. 5. The sulfonic acid compound is selected from the group consisting of dodecylbenzenesulfonic acid, dinonylnaphthalenedisulfonic acid, dinonylnaphthalenesulfonic acid, paratoluenesulfonic acid and methanesulfonic acid. the method of. 6. The method according to claim 1, wherein the amine compound has a boiling point within the range of 50 to 230 ° C. 7. The amine compound is dimethyloxazolidine, dialkylamine, diisopropylamine, di-n.
7. A method according to any one of claims 1 to 6 selected from the group consisting of: -propylamine, di-n-butylamine and diisobutylamine. 8. The reaction mixture (C) is a sulfonic acid compound 1
The method according to any one of claims 1 to 7, which is a reaction mixture of 4 to 30 mol of an amine compound. 9. The coating composition according to claim 1, wherein the coating composition contains 0.2 to 2 parts by weight of the reaction mixture (C) in terms of the sulfonic acid compound per 100 parts by weight of the resin composition. Method. 10. The coating composition contains the coloring pigment (D) in an amount of 5 to 120 parts by weight per 100 parts by weight of the resin composition.
10. The method according to any one of 9 to 10. 11. The method according to claim 1, wherein the coating material further contains fine silica powder. 12. The coating composition further contains an aggregate.
The method according to any one of 1 to 11. 13. The method according to claim 1, wherein the strip-shaped article to be coated moves at a speed of 10 m / min or more. 14. The method according to claim 1, wherein the strip-shaped article to be coated is a strip-shaped metal plate having a primer coating film formed thereon. 15. The belt-shaped article to be coated comprises a belt-shaped metal plate, a primer coating film, and a colored protective coating film sequentially formed on the primer coating film. the method of. 16. The method according to claim 1, wherein a plurality of spray coating devices are fixed. 17. The method according to claim 1, wherein the spray coating is performed while simultaneously reciprocating a plurality of spray coating devices in the same direction for a short distance. 18. The method according to claim 1, wherein the spray coating device is a multi-nozzle spray gun having two or more adjacent paint discharge nozzles. 19. A matte multicolor pattern coating film-coated plate obtained by the method for forming a multicolor pattern coating film according to claim 1.